﻿<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>复选框点亮按钮</title>
    <script type="text/javascript">
        function checkReg(){
            let cb =  document.getElementById("cb");
            let btn = document.getElementById("btn");
            if(cb.checked){
                btn.disabled = false;
            }else{
                btn.disabled = true;
            }
        }
        
    </script>
</head>
<body>
<input type="checkbox" id="cb" onclick="checkReg()">我同意
<input type="button" id="btn" value="下一步" disabled="true">
</body>
</html>